The FREQue II Ring Modulator from DACS


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The FREQue II I used the original FREQue Ring Modulator and Frequency Shifter (pronounced "freak") a couple of years ago and I looked forward to this updated, enhanced version from the DACS FwS Series of Effectors. I found this two-rack space, two-channel unit to modify music and individual sounds in ways from subtle to otherworldly! Although ring modulation is a simple process and has been around for years, all designs have been plagued by excessive leakage of the unprocessed audio and modulation signals into the processed output. Digital Audio and Computer Systems (DACS) developed a device that reduced this leakage for a purer effect with lower noise.


Ease of Use: 4
Value: 4
Functionality: 5

What Is A Ring Modulator?

A ring modulator is an all analog device that mixes FREQUENCIES of sound together and produces two products. With an ordinary audio mixer, the sum or the output is always the input signals' VOLTAGES added together in whatever mix ratio you have them. So if you mix two guitar tracks together on your mixer with one mixer fader twice as high as the other, the output balance is made up of one guitar twice as loud as the other. It is always a single product: a simple arithmetic sum of the inputs' analog voltages.

The output of a ring modulator is the algebraic sum of the sum and difference of the audio signals' frequencies, not voltages. Both the Sum and the Difference of the frequencies of the sound signals at the Music and Mod inputs of the FREQue II are generated at the output of the ring modulator. For example: if you put a 100Hz tone in the Music input and a 75Hz signal in the Mod input, the output of the ring can be expressed as:

Output= (100Hz+75Hz)+(100Hz-75Hz) or 175Hz+25Hz

You will have two new sounds coming out: one at 75Hz above (the Sum) and one 75Hz below (the Difference) the 100Hz signal.

If you applied the same signal, lets use 100Hz again, to both the Mod and Music inputs signals, then the output frequency would be 200Hz and 0Hz. Expressed as:

Output= (100Hz+100Hz)+(100Hz-100Hz) or 200 Hz and 0Hz

You would end of with a single, perfect octave above the Music input signal.

Frequency Shifter

The second main function of the FREQue II is frequency shifting. The frequency shifter uses extra circuits that separate the sum and difference frequencies of the standard ring modulator outputs. Frequency shifting mode is activated when the FREQue button is pushed and the Mod frequency determines how far the frequency is shifted up or down. In this mode, the two ring modulator outputs become separate shift up and shift down outputs. This is not like using a harmonizer: you can shift all the frequencies of a kick drum down to the subsonic, where only elephants, whales and submarines will hear it. Furthermore, since this an analog process, there is no processing delay.

Rear Panel

The rear panel is the best way to familiarize yourself with this unit. I had to switch the IEC connector over to 110VAC operation since the unit came directly from 220VAC-land, England. There are two complete sets of input and output jacks for the two completely separate ring modulators called RM1 and RM2. I'll just cover RM1's jacks since both rings are alike and all jacks are duplicated for RM2.

CV1 or Control Voltage for RM1 is a voltage input for controlling the internal oscillator and adds to whatever you have dialed in on the front panel oscillator controls. For you synth tinkerers, control voltage inputs are volts/Hz types. OSC1 is an output jack for the internal oscillator.

MOD1 In is the modulation input jack for the signal you want to modulate the audio signal coming into the MUS1 input or music input jack. MOD1 and MUS1 are the main inputs to the ring. Modulations tones, LFOs or secondary signals should be fed into the MOD1 jack and music fed into the MUS1 jack. Finally, RM1 OUT is the output of the ring modulator and when FREQue mode is selected, RM1 becomes the frequency shifter output with shifted UP components. RM2 OUT is the output of the other ring modulator that becomes frequency shifter output with shifted DOWN components.

Front Panel

Starting from the left side, you'll see two sets of input LED meters, one for each ring modulator. You set levels for both the MOD and MUS inputs with these meters. There are two simple equalizers called Weight and Edge, one for each ring modulator's MUS input. Weight is an 80Hz bass shelving filter with a + or - 12dB range while Edge is an 8kHz treble shelving filter with also + or - 12dB range. I used these extensively in my sound designs to lessen or enhance certain parts of the sound.

The comprehensive oscillator controls are next. There is a lighted switch that connects the oscillator's output to the MOD input of the ring. This is the quick start method to get sounds because you'll have a simple source, the oscillator, modifying a complex source, music. I would suggest getting familiar with this box in this way first before processing music with other complex sources plugged into the MOD input.

Since the oscillator's range is from 0.1Hz to 16kHz, there are four ranges: 0.1Hz to 10Hz, 0.3Hz to 30Hz, 1Hz to 2kHz and 1kHz to 16kHz. These overlapping ranges you'll need for operational ease when using this wonderful unit. After you have selected the range of the oscillator, the Fine and Coarse controls get you exactly on the "sweet spot." This is when you'll discover that the ring modulator is really a musical instrument in that you will be "playing" with the oscillator control all the time. In fact the whole key with getting anything useful is by continuously "playing" with the controls following the changes in the music. This is not a "set and forget" can sound unbelievable one moment and inappropriate the next if you do not understand what is going on and readjust the controls in anticipation of the changes in the music.

The last button in the oscillator section is the OSC1 button that disconnects OSC1 from MOD1's input and routes OSC2 (from the RM2 side) to MOD1's input. This clever addition turns the unit into a stereo module with the same effect on both left and right channels. Stereo mode is probably the most impressive sounding mode when ring modulating tracks in your mix.

FM Operation

With the FM button pushed, you route OSC1 to CV2. So the FM Depth control adjusts the amount of frequency modulation of OSC2. OSC1 is modulating the frequency of OSC2 in this special submode. This produces a more complex and quirky effect that's especially wacky on percussion instruments. If OSC1 is very slow, below 1Hz, you'll achieve everything from phaser/flanger/filter sweep effects.

New Features on The FREQue II

The main news on the FREQue II over the original FREQue is the addition of the comprehensive on-board mixers and now all inputs and outputs are now fully balanced. On the right side of the front panel are the new Input and Output mixers. With the Input Mixer you can mix the levels of MOD1 and MUS1 along with MOD2 and MUS2. This saves a lot trouble getting levels exactly right coming into the unit. For the unit to work properly, input levels have to be from +2dBu to +12dBu up to a maximum of +18dBu. The Output Mixers are simple wet/dry balance knobs for each ring modulator output. You can mix between the Music input and the processed output of the ring. Great new features!

In the Studio

Using a ring modulator requires a bit of experimental time and I generally don't bore my clients while I fish around...I just do this sort of thing on my own time. I would be remiss if I didn't tell you that this is a fiddly unit but you will rewarded if you spend the time. For an veteran knob twister like me, I was in tweaker's heaven. I found the FREQue II just like the original except I had more control in dialing in the amount or depth of the intense effects possible. You can get the most intense tremolos, auto panning and harmonically modified harmonic structures. I like using filter-like sweeps to liven up some boring synth pads. The frequency shifting I find extremely useful and there's sounds you can get from no other unit or plug-in. Pitch shifting works the best for fixed pitch instruments: percussion. As I said you can shift bass drums down or up anywhere you like for a super clean sound with no noise or digital artifacts. Using the FM mode also works great on percussion instruments and atonal noises and background washes.

The FREQue II is a better ring modulator with even more versatility now and, like the original FREQue, has the least amount of leakage of the modulator signal at the output of any I have tried before. I found the unit very clean and a great way to add very unique effects to your sound designs.

Digital Audio and Computer System Ltd. is at Stonehills, Shields Road, Pelaw, Gateshead, Tyne and Wear, NE10 0HW UK. Their products are distributed in US by Independent Audio at 207/773-2424. Web to:

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